![sip 404 not found sip 404 not found](https://www.dialogic.com/webhelp/img1010/10.5.3/webhelp/cf_sip_rh_cause3_404.png)
If the URI cached from the Contact header field fails, the Request-URI from the redirected request MAY be tried again a single time.
![sip 404 not found sip 404 not found](https://www.researchgate.net/profile/Vasilios-Katos/publication/267632278/figure/fig7/AS:668511378608132@1536396941120/Unsuccessful-SIP-INVITE-negotiations-see-online-version-for-colours_Q320.jpg)
If there is no explicit expiration time, the address is only valid once for recursing, and MUST NOT be cached for future transactions. Both proxies and UAs MAY cache this URI for the duration of the expiration time. The duration of the validity of the Contact URI can be indicated through an Expires header field or an expires parameter in the Contact header field. The Request-URI of the new request uses the value of the Contact header field in the response. The requesting client SHOULD retry the request at the new address(es) given by the Contact header field.
#SIP 404 NOT FOUND UPDATE#
The requester SHOULD update any local directories, address books, and user location caches with this new value and redirect future requests to the address(es) listed. The user can no longer be found at the address in the Request-URI, and the requesting client SHOULD retry at the new address given by the Contact header field.
![sip 404 not found sip 404 not found](https://present5.com/presentation/6e3f29d9944e20bf5589f2a2380155c8/image-42.jpg)
This status response is appropriate if the callee can be reached at several different locations and the server cannot or prefers not to proxy the request. However, this specification does not define any standard for such automatic selection. UAs MAY use the Contact header field value for automatic redirection or MAY ask the user to confirm a choice. Unlike HTTP, the SIP response MAY contain several Contact fields or a list of addresses in a Contact field. The choices SHOULD also be listed as Contact fields. However, no MIME types have been defined for this message body. The response MAY include a message body containing a list of resource characteristics and location(s) from which the user or UA can choose the one most appropriate, if allowed by the Accept request header field. The address in the request resolved to several choices, each with its own specific location, and the user (or UA) can select a preferred communication end point and redirect its request to that location. The information returned with the response depends on the method used in the request.ģxx responses give information about the user's new location, or about alternative services that might be able to satisfy the call. The Reason-Phrase, header fields, or message body MAY be used to convey more details about the call progress. The 183 (Session Progress) response is used to convey information about the progress of the call that is not otherwise classified. The server MAY issue several 182 (Queued) responses to update the caller about the status of the queued call. The reason phrase MAY give further details about the status of the call, for example, "5 calls queued expected waiting time is 15 minutes". When the callee becomes available, it will return the appropriate final status response. The called party is temporarily unavailable, but the server has decided to queue the call rather than reject it.
#SIP 404 NOT FOUND CODE#
This response MAY be used to initiate local ringback.Ī server MAY use this status code to indicate that the call is being forwarded to a different set of destinations. The UA receiving the INVITE is trying to alert the user. The 100 (Trying) response is different from other provisional responses, in that it is never forwarded upstream by a stateful proxy. This response, like all other provisional responses, stops retransmissions of an INVITE by a UAC. This response indicates that the request has been received by the next-hop server and that some unspecified action is being taken on behalf of this call (for example, a database is being consulted). Provisional (1xx) responses MAY contain message bodies, including session descriptions. They never cause the client to send an ACK. Note that 1xx responses are not transmitted reliably. A server sends a 1xx response if it expects to take more than 200 ms to obtain a final response. Provisional responses, also known as informational responses, indicate that the server contacted is performing some further action and does not yet have a definitive response. Other HTTP/1.1 response codes SHOULD NOT be used. Not all HTTP/1.1 response codes are appropriate, and only those that are appropriate are given here. The SIP response codes are consistent with, and extend to, HTTP/1.1 response codes.